This invention relates generally to an improved detonator, and more particularly, to a semiconductor bridge (SCB) actuated detonator for high explosives.
The inexpensive and reliable ignition of explosives is a desirable goal for obvious cost and safety reasons. To this end, the semiconductor bridge (SCB) igniter of R. Bickes et al., U.S. Pat. No. 4,708,060, was developed. This invention has a short semiconductor bridge between two spaced metal pads on a nonconducting substrate. The heavily doped, approximately one ohm, bridge is in contact with an explosive material. The bridge is easily designed to not fire when a "no fire" current is applied, but to fire when a higher "fire" current is applied. As disclosed, application of a 15A, 15 us current pulse through the SCB produces a plasma discharge that ignites the explosive material at a relatively slow rate. Such ignition is suitable for actuators, gas generators and rocket motors, but is not fast enough for other applications.
In some applications, high explosive powders are initiated by the mechanical impulse provided by a slapper detonator, a piece of hard material rapidly propelled against the powder by an electrically exploded metal foil. Because a slapper can generate detonation promptly, this technology can be used wherever exploding bridge wire devices are normally used to initiate these high explosives. The use of a slapper initiator permits the use of more stable explosives, an important safety consideration.
In addition, exploding bridge wires have also been used for direct initiation of high explosives, a construction that eliminates the slapper structure.